Power quality measuring and monitoring is an important concept in the power industry and generally relates to devices, methods and systems that ensure that an AC power system is consistent, free from harmonic content and/or remains uninterrupted. For example, a power quality meter is one type of device that can give some form of harmonic content indication. Another example of a power quality and monitoring device is a power transfer switch that is used to switch electrical loads between two independent sources of power so as to prevent disruption in service. A principal goal of a power transfer switch system is to ensure that the electrical load is supplied with an acceptable source of power at a high rate of availability and to minimize load disruptions.
The above devices and systems are normally located in housings for enclosing and protecting the electrical equipment from hostile environments from rain, snow, insect damage, animal damage, human tampering, and so forth. Typically these electrical enclosures have a front panel with portions having cut outs to expose one or more current meters, volt meters, circuit breakers, disconnects, switches, push buttons, and the like that must be mounted inside to the backside surface of the flat panel and hardwired amongst the various transfer switch components. In order to replace or service these fixed mounted interfaces, a trained service operator must typically open the electrical enclosure via a service entrance and perform servicing work from within the inside the enclosure. Because of the risks of electrical shock and arc flash, especially if the electrical equipment comprises medium voltage or high voltage transfer switches, all sources of electrical power must be disconnected from the equipment housed inside the electrical enclosure. In modern transfer switch systems, for example, the user interfaces are typically integrated electronic assemblies presented to the user through the cutout in the electrical enclosure, and is interconnected by hard wiring to other devices within the electrical enclosure housing the transfer switch. In such systems, in order to reduce the dangers of electrical shock or arcing, servicing of the user interface requires that the power to the transfer switch be disconnected. This disconnecting of the power can result in extended periods without electrical power. This is true regardless of whether the maintenance work is to be performed on the high voltage switching mechanism or the low voltage control circuits of the switch interface itself.
As such, there is a need in the power quality measuring and monitoring technology field for a user or operator interface that avoids these dangers. The interface must be serviceable or capable of replacement or expansion without the loss or interruption of existing service. The present disclosure, although generally applicable to a number of power quality and monitoring systems, finds specific applicability with respect to transfer switch systems by avoiding the need to disconnect the power to the transfer switch while allowing maintenance of the user interface. Additionally, the present disclosure provides a method for replacing the user interface without the need for disconnection of the power load to the transfer switch. These and other benefits of the presently disclosed systems and methods will become more evident from a reading of the following description and a review of the attached drawings.